Note that the box was also different for this version. And nearly all looks like "dirty" by this age. The problem is most likely the glue which was used for the label. It seems to come through the label and stain it...
Thanks! Yes, I have seen these auctions. The 99 euros vendor does not respond to my request for extra pictures. That cartridge looks very moldy, but is in fact one that seems to be in pretty good condition.
I think I figured out why this game's labels always seem to be moldy. Green Beret is such a shit game, it's only natural for its label to reflect its contents.